Install google-java-format 1.7 alongside 1.6

Change-Id: Ia9414ec669449ee24e274c8a12e3d14f94ee6da2
diff --git a/jenkins-docker/slave-bazel/Dockerfile b/jenkins-docker/slave-bazel/Dockerfile
index 65af3ca..cba404f 100644
--- a/jenkins-docker/slave-bazel/Dockerfile
+++ b/jenkins-docker/slave-bazel/Dockerfile
@@ -7,6 +7,7 @@
     cd /tmp &&  git clone -b stable-2.15 --recursive https://gerrit.googlesource.com/gerrit && \
     cd /tmp/gerrit && \
     ./tools/setup_gjf.sh 1.6 && \
+    ./tools/setup_gjf.sh 1.7 && \
     ( bazel build //... || true ) && \
     git checkout -f stable-2.16 && git submodule update --init && ( bazel build //... || true ) && \
     git checkout -f master && git submodule update --init && ( bazel build //... || true ) && \